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    <title>Document</title>
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  <body>
    <script>
      // 1. 类的继承基础使用
      /* class Father {
        constructor() {}
        money() {
          console.log(100)
        }
      }
      class Son extends Father {}
      var son = new Son()
      son.money() */

      // 2. 类继承的super关键字使用
      /* 父类 */
      class Father {
        constructor(x, y) {
          this.x = x
          this.y = y
        }
        sum() {
          console.log(this.x + this.y)
        }
      }
      /* 子类 */
      class Son extends Father {
        constructor(x, y) {
          super(x, y) // 通过super关键字调用了父类中的构造函数
        }
      }
      var son = new Son(1, 2)
      var son1 = new Son(11, 22)
      son.sum()
      son1.sum()
    </script>
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